US6647026B1 - Frame phase synchronous system and a method thereof - Google Patents

Frame phase synchronous system and a method thereof Download PDF

Info

Publication number
US6647026B1
US6647026B1 US09/401,182 US40118299A US6647026B1 US 6647026 B1 US6647026 B1 US 6647026B1 US 40118299 A US40118299 A US 40118299A US 6647026 B1 US6647026 B1 US 6647026B1
Authority
US
United States
Prior art keywords
shift value
node
frame phase
phase difference
respect
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
US09/401,182
Other languages
English (en)
Inventor
Hironao Tanaka
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NEC Corp
Original Assignee
NEC Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by NEC Corp filed Critical NEC Corp
Assigned to NEC CORPORATION reassignment NEC CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: TANAKA, HIRONAO
Application granted granted Critical
Publication of US6647026B1 publication Critical patent/US6647026B1/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L7/00—Arrangements for synchronising receiver with transmitter
    • H04L7/04—Speed or phase control by synchronisation signals
    • H04L7/08—Speed or phase control by synchronisation signals the synchronisation signals recurring cyclically
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/54—Store-and-forward switching systems 
    • H04L12/56—Packet switching systems
    • H04L12/5601—Transfer mode dependent, e.g. ATM
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/02—Details
    • H04J3/06—Synchronising arrangements
    • H04J3/0635—Clock or time synchronisation in a network
    • H04J3/0682—Clock or time synchronisation in a network by delay compensation, e.g. by compensation of propagation delay or variations thereof, by ranging
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/54—Store-and-forward switching systems 
    • H04L12/56—Packet switching systems
    • H04L12/5601—Transfer mode dependent, e.g. ATM
    • H04L2012/5672—Multiplexing, e.g. coding, scrambling
    • H04L2012/5674—Synchronisation, timing recovery or alignment

Definitions

  • the present invention relates to a frame phase synchronous system for adjusting phase synchronization between respective nodes such as relay nodes, switching nodes and base station nodes in a digital mobile communications system and, more particularly, to a frame phase synchronous system for measuring a frame phase difference by using a loop-back function of an ATM (ASYNCHRONOUS TRANSFER MODE) cell and independently matching the frame phases between the individual nodes.
  • respective nodes such as relay nodes, switching nodes and base station nodes in a digital mobile communications system
  • ATM ASYNCHRONOUS TRANSFER MODE
  • a master-slave synchronous system for realizing frequency synchronization between a master device and a slave device, wherein the master device transmits a transmission signal which is synchronized with a reference frequency of a reference clock in the master device, and the slave device extracts a clock signal from the received transmission signal and makes an oscillator of the device itself synchronized in phase with it.
  • a master-slave synchronous system is applied in which a master node supplies a frame phase synchronous signal to switching nodes and base station nodes in the network via an STM (SYNCHRONOUS TRANSFER MODE) network.
  • STM SYNCHRONOUS TRANSFER MODE
  • a synchronizing accuracy can not be set to under 125 ⁇ sec. at the minimum in terms of such a condition that the STM network be used. This is because it is prescribed in the STM network that the synchronization is executed by using one bit determined in one time slot, and hence the synchronizing accuracy can not be set to a one time slop length (125 ⁇ sec.) or under.
  • a frame phase synchronous system according to the present invention is characterized by having the following constructions in order to solve the problems described above.
  • a frame phase synchronous system for adjusting phase synchronization in a digital mobile communications system comprises: a relay node which measures a frame phase difference with respect to other relay nodes using a method of calculating a frame phase difference from a propagation delay time through ATM cell loop-back, also obtains an optimum shift value as a first shift value for adjusting the phase synchronous in the relay node, and for notifies the first shift value to a switching node connected to as a slave; a switching node which measures a frame phase difference with respect to the host relay node and a frame phase difference with respect to a base station node as the slave, obtains a second shift value by adding the notified first shift value to a shift value derived from the measured frame phase difference with respect to the host relay node for adjusting the phase synchronous in the switching node, and also obtains a third shift value by adding the second shift value to a shift value derived from the measured frame phase difference with respect to the base station node as the slave for notifying the third shift value to the base station no
  • the relay node further comprises: a first frame phase difference adjusting unit which measures a frame phase difference with respect to other relay nodes, and obtains an optimum shift value as a first shift value for adjusting the phase synchronous in the relay node; and a first shift value notifying unit which notifies the first shift value to the switching node accommodated as a slave.
  • the switching node further comprises: a frame phase difference measuring unit which measures a frame phase difference with respect to the host relay node and a frame phase difference with respect to the base station node as the slave; a second frame phase difference adjusting unit which obtains a second shift value by adding the notified first shift value to a shift value derived from the measured frame phase difference with respect to the host relay node for adjusting the phase synchronous in the switching node; and a third frame phase difference adjusting unit which obtains a third shift value by adding the second shift value to a shift value derived from the measured frame phase difference with respect to the base station node accommodated as the slave for notifying the third shift value as an shift value to be adjusted in the base station node.
  • a method of frame phase synchronous in a digital mobile communications system in which a plurality of relay nodes, switching nodes as slave nodes of the relay node, and base station nodes as slave nodes of the switching node are provided, according to the present invention is characterized by having the following constructions:
  • FIG. 1 is a diagram showing an example of architecture of a mobile communications network.
  • FIG. 2 is a block diagram showing a construction of a frame phase synchronous part in a relay node according to the present invention.
  • FIG. 3 is a block diagram showing a construction of a frame phase synchronous part in a switching node according to the present invention.
  • FIG. 4 is a block diagram showing a construction of a frame phase synchronous part in a base station node according to the present invention.
  • FIG. 5 is a sequence diagram showing a procedure of executing a phase shift according to the present invention.
  • FIG. 6 is a sequence diagram showing a one-way propagation delay time measurement using an ATM cell loop-back.
  • FIG. 1 An architecture of a digital mobile communication system in one embodiment of the present invention will be explained referring to FIG. 1 .
  • respective nodes such as a relay node 1 , a switching node 2 and a base station node 3 are connected via an ATM transmission line 4 , and all the nodes establish clock synchronization.
  • the base station node 3 is a radio base station for providing radio service area for mobile nodes.
  • the switching node 2 is a mobile switching center for switching calls to/from mobile nodes through the radio base station, and controls radio base stations for the mobile communication.
  • the relay node 1 is also a mobile switching center, but only handles relaying traffic in the mobile communication network.
  • the relay node 1 can be a gateway switching center to interface with other communication network such as a fixed communication network.
  • All the relay nodes are connected each other with a mesh type connection by the ATM transmission lines.
  • the relay node and a plurality of switching nodes accommodated in the relay node are also connected via the ATM transmission lines. Further, each of the switching nodes accommodates a plurality of base station nodes.
  • Each relay node includes a communication control unit 11 for performing communications with other relay nodes and with the switching nodes accommodated therein as slaves. Further, the relay node includes a frame phase difference measuring unit 12 for measuring a frame phase difference between the relay nodes by using an ATM cell loop-back function, a shift value- 1 calculating unit 13 for calculating a shift value- 1 on the basis of an average value of the frame phase differences from other relay nodes which have been measured by the frame phase difference measuring unit, and a shift value- 1 storage unit 14 for storing the calculated shift value- 1 .
  • the relay node includes a shift value- 1 notifying unit 15 for notifying of the shift value- 1 the switching nodes accommodated therein as the slaves, and a phase shift processing unit 16 for executing a phase shift of the relay node itself in accordance with the shift value- 1 .
  • the relay node includes a frame phase synchronous signal device 17 for retaining clock synchronization established within the system.
  • Each of the switching nodes includes a communication control unit 21 for implementing communications with the host relay node and the base station nodes accommodated therein as slaves. Further, the switching node includes a frame phase difference measuring unit 22 for measuring frame phase differences between the host relay node and the switching node itself and between the switching node itself and all the base station nodes accommodated therein as the slaves by using the ATM cell loop-back function.
  • the switching node includes a shift value- 2 calculating unit 23 for calculating a shift value- 2 by adding the shift value- 1 of which the host relay node has notified to the frame phase difference between the host relay node and the switching node itself which has been measured by the frame phase difference measuring unit, and a shift value- 2 storage unit 24 for storing the calculated shift value- 2 .
  • the switching node includes a shift value- 3 calculating unit 25 for calculating a shift value- 3 per base station by adding the shift value- 2 to the frame phase difference between the switching node itself and the all the base station nodes accommodated therein as the slaves which has been measured by the frame phase difference measuring unit, a shift value- 3 storage unit 26 for storing the calculated shift value- 3 , and a phase shift processing indication unit 27 for giving an indication to execute a phase shift as well as notifying each base station node as the slave of the shift value- 3 .
  • the switching node includes a phase shift processing unit 28 for executing a phase shift of the switching node itself in accordance with the shift value- 2 . Furthermore, the switching node includes a frame phase synchronous signal device 29 for retaining the clock synchronization established within the system.
  • Each of the base station nodes includes a communication control unit 31 for implementing communications with the host relay node. Further, the base station node includes a phase shift processing unit 32 for executing a phase shift of the base station node itself in accordance with the shift value- 3 of which the host switching node has notified. Furthermore, the base station node includes a frame phase synchronous signal device 33 for retaining the clock synchronization established within the system.
  • the relay node 1 and the switching node 2 measure frame phase differences between the respective nodes such as between the respective relay nodes, between the relay node and the switching node, and between the switching node and the base station node (S 11 , S 21 ).
  • the relay node 1 measures, based on the ATM cell loop-back, the frame phase difference with respect to other relay nodes
  • the switching node measures, based on the ATM cell loop-back, the frame phase differences with respect to the host relay node and with all the base station nodes as the slaves. This frame phase difference measurement will hereinafter be explained in greater details referring to FIG. 6 .
  • the measuring side node writes a time T 1 to a time data segment of the ATM cell for indicating the time when the cell is transmitted, and transmits this ATM cell to a loop-back side node via the communication control unit ( 11 or 21 ) from the frame phase difference measuring unit ( 12 or 22 ) (S 61 ).
  • the loop-back side node upon receiving the ATM cell transmitted from the measuring side node (S 62 ), writes a receiving time (T 2 ) and a send-back time (T 3 ) of the same cell to the time data segment of the received cell, and sends the cell back to the measuring side node at the time T 3 (s 63 ).
  • the measuring side node upon receiving the cell looped back, records a receiving time T 4 (S 64 ).
  • the frame phase difference measuring unit ( 12 or 22 ) calculates a one-way propagation delay time between the measuring side node and the loop-back side node from the obtained data (S 65 )
  • the one-way propagation delay time dm is obtained by an average of T 2 ⁇ T 1 and T 4 ⁇ T 3 . Further, the frame phase difference is calculated.
  • the ATM cell transmitted at the time T 3 in the loop-back side node is to be received by the measuring side node at time T 3 +dm after the one-way propagation delay time dm has elapsed.
  • the ATM cell receiving time T 4 in the measuring side node must be equal to T 3 +dm. Accordingly, if the frame phase of the measuring side node is not coincident with the frame phase in the loop-back side node, the frame phase difference is obtained by T 4 ⁇ T 3 ⁇ dm.
  • This frame phase difference measurement is not required to be executed strictly in time-synchronization, and may therefore be done when a maintenance worker makes a time correction by a manual time adjustment.
  • the shift value- 1 calculating unit 13 of each relay node calculates the shift value- 1 by taking an average value of the frame phase differences with respect to other relay nodes which are obtained through the frame phase difference measurement by the frame phase difference measuring unit 12 (S 12 ), and makes the shift value- 1 storage unit 14 to store this value (S 13 ). Further, the shift value- 1 notifying unit 15 notifies of the shift value- 1 all the switching nodes accommodated as the slaves (S 14 ).
  • the shift value- 2 calculating unit 23 calculates a shift value- 2 by adding the frame phase difference with respect to the host relay node which has been obtained through the frame phase difference measurement, to the shift value- 1 of which the host relay node has notified (S 22 ), and makes the shift value- 2 storage unit 24 to store this value (S 23 ). Furthermore, the shift value- 3 calculating unit calculates a shift value- 3 per base station node by adding the frame phase difference with respect to each base station node accommodated as the slave which has been obtained through the frame phase difference measurement, to the shift value- 2 (S 24 ), and makes the shift value- 3 storage unit 26 to store with this value (S 25 ).
  • each relay node and switching node execute, in a state of being stored with the shift values 1 , 2 and 3 , the phase shifts at a predetermined time specified as every target time.
  • the phase shift processing unit 16 reads at the predetermined time the shift value- 1 previously stored in the shift value- 1 storage unit 14 , and executes the phase shift for correcting the frame phase difference with respect to the frame phase synchronous signal device 17 (S 15 ).
  • the phase shift processing unit 28 reads at the same predetermined time as that in the relay node the shift value- 2 previously stored in the shift value- 2 storage unit 24 , and executes the phase shift for correcting the frame phase difference with respect to the frame phase synchronous signal device 29 (S 27 )
  • the switching node 2 controls the phase shift of the base station node 3 accommodated as the slave, and hence, before effecting the phase shift (S 27 ) of the node itself, the phase shift processing indication unit 27 reads the shift value- 3 from the shift value- 3 storage unit 26 , transmits the corresponding shift value- 3 to each base station node 3 accommodated as the slave, and gives an indication to execute the phase shift process (S 26 ).
  • the phase shift processing unit 32 executes the phase shift for correcting the frame phase difference with respect to the frame phase synchronous signal device 33 (S 31 ).
  • the shift value- 1 is set as the average value of the frame phase differences between the relay nodes, however, if the number of nodes increases, a median or a mode may also be set as the shift value- 1 in order to avoid an influence of scatter. Further, the ATM transmission line has a large scatter of delay fluctuations, and therefore an average value or a median or a mode may also be taken by carrying out the measurement a plurality of times when measuring the phase difference between the respective nodes.
  • the frame phase difference between the relay node and the switching nodes accommodated as the slaves is measured in the switching node, however, this construction may be made so that the measurement is effected in the relay node. Further, the frame phase difference between the switching node and the base station nodes accommodated as the slaves, is measured in the switching node, however, this construction may be made so that measurement is implemented in the base station node.
  • the present invention it is feasible to establish the high-accuracy frame phase synchronization within the mobile communication network because of using the ATM transmission line for measuring the transmission delay time. Further, there exists no master node for the frame phase in the network as a whole, and, because of the frame phase being determined by a statistic average between the relay nodes, the operation management is facilitated as well as increasing a redundancy of retaining the frame phase as the network.
  • the frame synchronization between the relay nodes is corrected by the mutual synchronizing system, while the frame synchronization between the relay node and the switching node and between the switching node and the base station node, is corrected by the master-slave system, and, with this construction, the base station does not require the phase difference calculating device, thereby exhibiting such an effect as to facilitate structuring.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Data Exchanges In Wide-Area Networks (AREA)
  • Synchronisation In Digital Transmission Systems (AREA)
US09/401,182 1998-09-24 1999-09-23 Frame phase synchronous system and a method thereof Expired - Fee Related US6647026B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP10-269892 1998-09-24
JP26989298A JP2000101597A (ja) 1998-09-24 1998-09-24 ノード間フレーム位相同期方式及び方法

Publications (1)

Publication Number Publication Date
US6647026B1 true US6647026B1 (en) 2003-11-11

Family

ID=17478680

Family Applications (1)

Application Number Title Priority Date Filing Date
US09/401,182 Expired - Fee Related US6647026B1 (en) 1998-09-24 1999-09-23 Frame phase synchronous system and a method thereof

Country Status (7)

Country Link
US (1) US6647026B1 (id)
JP (1) JP2000101597A (id)
KR (1) KR100353107B1 (id)
AU (1) AU757626B2 (id)
ID (1) ID24126A (id)
SG (1) SG81312A1 (id)
TW (1) TW437226B (id)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6728492B1 (en) * 2000-12-01 2004-04-27 Alcatel 40 Gbit/s SONET framer with multiple clock-crossing capability
US20070140127A1 (en) * 2005-12-19 2007-06-21 Skypilot Network, Inc. Method and apparatus for efficient transfer of data over a network
US20070281643A1 (en) * 2006-05-30 2007-12-06 Hitachi Kokusai Electric Inc. Radio communication system and overhang station apparatus
US20090268758A1 (en) * 2007-11-14 2009-10-29 Qing Zhang Method, system and apparatus for synchronizing time in time-division multiplexing system
US8437371B2 (en) * 2006-08-22 2013-05-07 Alcatel Lucent Gateway, base station, communication network and synchronization method thereof
US20140235181A1 (en) * 2013-02-19 2014-08-21 Kabushiki Kaisha Tokai Rika Denki Seisakusho Propagation time measurement device and electronic key system
EP2183886A4 (en) * 2007-08-15 2015-03-04 Adc Telecommunications Inc DELAY HANDLING FOR DISTRIBUTED COMMUNICATION NETWORKS
US10247764B2 (en) 2013-07-25 2019-04-02 Daihen Corporation Method for controlling devices provided with communication function, and device used in implementing the method
CN110635998A (zh) * 2018-06-22 2019-12-31 华为技术有限公司 一种数据传输方法、相关设备及计算机存储介质

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003087175A (ja) * 2001-09-10 2003-03-20 Hitachi Kokusai Electric Inc メッシュ型無線局通信システム
JP4868212B2 (ja) * 2005-12-15 2012-02-01 横河電機株式会社 時刻情報通信システム
US7539889B2 (en) * 2005-12-30 2009-05-26 Avega Systems Pty Ltd Media data synchronization in a wireless network
JP6691730B2 (ja) * 2013-07-25 2020-05-13 株式会社ダイヘン インバータ回路を制御する制御回路、当該制御回路を備えたインバータ装置、当該インバータ装置を備えた電力システム、および、制御方法
JP6983726B2 (ja) * 2018-06-01 2021-12-17 株式会社東芝 分散アンテナシステム及び同期方法
KR20220063759A (ko) * 2020-11-09 2022-05-17 션쩐 텐센트 컴퓨터 시스템즈 컴퍼니 리미티드 다중 비트 양자 피드백 제어를 위한 양자 측정 및 제어 시스템
CN113011591B (zh) * 2020-11-09 2023-07-28 深圳市腾讯计算机系统有限公司 一种用于多比特量子反馈控制的量子测控系统

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4811365A (en) 1986-11-07 1989-03-07 Manno Phillip E Communications system
JPH03270440A (ja) 1990-03-20 1991-12-02 Mitsubishi Electric Corp パケット多重化装置のための同期時刻設定方式
JPH0746659A (ja) 1993-08-02 1995-02-14 Nippon Telegr & Teleph Corp <Ntt> 移動通信の基地局間フレーム同期方法
JPH07131853A (ja) 1993-11-05 1995-05-19 N T T Idou Tsuushinmou Kk 移動通信方式
EP0718995A1 (en) 1994-12-20 1996-06-26 International Business Machines Corporation Apparatus and method for synchronizing clock signals for digital links in a packet switching mode
JPH0946325A (ja) 1995-07-26 1997-02-14 Nec Telecom Syst Ltd 時刻同期方式
EP0776104A2 (en) 1995-11-24 1997-05-28 Alcatel Method and network node for resynchronizing frames in a synchronous digital transmission system
US5963605A (en) * 1996-05-22 1999-10-05 Nec Corporation Burst frame phase synchronizing circuit and burst frame phase synchronizing method utilizing a frame synchronizing signal satisfying a calculated protection condition
US6373834B1 (en) * 1997-12-19 2002-04-16 Telefonaktiebolaget Lm Ericsson Synchronization for cellular telecommunications network

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR910005334A (ko) * 1989-08-17 1991-03-30 서원석 극소형 변압기
JP2861955B2 (ja) * 1996-07-24 1999-02-24 日本電気株式会社 局間位相同期システム

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4811365A (en) 1986-11-07 1989-03-07 Manno Phillip E Communications system
JPH03270440A (ja) 1990-03-20 1991-12-02 Mitsubishi Electric Corp パケット多重化装置のための同期時刻設定方式
JPH0746659A (ja) 1993-08-02 1995-02-14 Nippon Telegr & Teleph Corp <Ntt> 移動通信の基地局間フレーム同期方法
JPH07131853A (ja) 1993-11-05 1995-05-19 N T T Idou Tsuushinmou Kk 移動通信方式
EP0718995A1 (en) 1994-12-20 1996-06-26 International Business Machines Corporation Apparatus and method for synchronizing clock signals for digital links in a packet switching mode
JPH0946325A (ja) 1995-07-26 1997-02-14 Nec Telecom Syst Ltd 時刻同期方式
EP0776104A2 (en) 1995-11-24 1997-05-28 Alcatel Method and network node for resynchronizing frames in a synchronous digital transmission system
US5963605A (en) * 1996-05-22 1999-10-05 Nec Corporation Burst frame phase synchronizing circuit and burst frame phase synchronizing method utilizing a frame synchronizing signal satisfying a calculated protection condition
US6373834B1 (en) * 1997-12-19 2002-04-16 Telefonaktiebolaget Lm Ericsson Synchronization for cellular telecommunications network

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6728492B1 (en) * 2000-12-01 2004-04-27 Alcatel 40 Gbit/s SONET framer with multiple clock-crossing capability
US8406139B2 (en) * 2005-12-19 2013-03-26 Trilliant Networks, Inc. Method and apparatus for efficient transfer of data over a network
US20070140127A1 (en) * 2005-12-19 2007-06-21 Skypilot Network, Inc. Method and apparatus for efficient transfer of data over a network
US7826374B2 (en) * 2005-12-19 2010-11-02 Trilliant Networks, Inc. Method and apparatus for efficient transfer of data over a network
US20110058494A1 (en) * 2005-12-19 2011-03-10 Trilliant Networks, Inc. Method and apparatus for efficient transfer of data over a network
US20070281643A1 (en) * 2006-05-30 2007-12-06 Hitachi Kokusai Electric Inc. Radio communication system and overhang station apparatus
US7680095B2 (en) * 2006-05-30 2010-03-16 Hitachi Kokusai Electric Inc. Radio communication system and overhang station apparatus
US8437371B2 (en) * 2006-08-22 2013-05-07 Alcatel Lucent Gateway, base station, communication network and synchronization method thereof
EP3540982A1 (en) * 2007-08-15 2019-09-18 CommScope Technologies LLC Delay management for distributed communications network
EP2183886A4 (en) * 2007-08-15 2015-03-04 Adc Telecommunications Inc DELAY HANDLING FOR DISTRIBUTED COMMUNICATION NETWORKS
EP3188381A1 (en) * 2007-08-15 2017-07-05 CommScope Technologies LLC Delay management for distributed communications networks
US8054860B2 (en) * 2007-11-14 2011-11-08 Huawei Technologies Co., Ltd. Method, system and apparatus for synchronizing time in time-division multiplexing system
US20090268758A1 (en) * 2007-11-14 2009-10-29 Qing Zhang Method, system and apparatus for synchronizing time in time-division multiplexing system
US20140235181A1 (en) * 2013-02-19 2014-08-21 Kabushiki Kaisha Tokai Rika Denki Seisakusho Propagation time measurement device and electronic key system
US9065841B2 (en) * 2013-02-19 2015-06-23 Kabushiki Kaisha Tokai Rika Denki Seisakusho Propagation time measurement device and electronic key system
US10247764B2 (en) 2013-07-25 2019-04-02 Daihen Corporation Method for controlling devices provided with communication function, and device used in implementing the method
US11029345B2 (en) 2013-07-25 2021-06-08 Daihen Corporation Method for controlling devices provided with communication function, and device used in implementing the method
US11624760B2 (en) 2013-07-25 2023-04-11 Daihen Corporation Method for controlling devices provided with communication function, and device used in implementing the method
CN110635998A (zh) * 2018-06-22 2019-12-31 华为技术有限公司 一种数据传输方法、相关设备及计算机存储介质
CN110635998B (zh) * 2018-06-22 2021-10-26 华为技术有限公司 一种数据传输方法、相关设备及计算机存储介质
US11510115B2 (en) 2018-06-22 2022-11-22 Huawei Technologies Co.. Ltd. Data transmission with a user plane network element method, related device, and computer storage medium

Also Published As

Publication number Publication date
JP2000101597A (ja) 2000-04-07
ID24126A (id) 2000-07-06
AU5008999A (en) 2000-03-30
TW437226B (en) 2001-05-28
KR100353107B1 (ko) 2002-09-16
SG81312A1 (en) 2001-06-19
KR20000023425A (ko) 2000-04-25
AU757626B2 (en) 2003-02-27

Similar Documents

Publication Publication Date Title
US6647026B1 (en) Frame phase synchronous system and a method thereof
CN111585683B (zh) 一种面向时间敏感网络的高可靠时钟同步系统及方法
AU752818B2 (en) Synchronization for cellular telecommunications network
US7590151B2 (en) Method and apparatus for aligning time references when separated by an unreliable data packet network
US8416812B2 (en) Network timing synchronization systems
US6920155B2 (en) Embedded loop delay compensation circuit for multi-channel transceiver
US6665316B1 (en) Organization of time synchronization in a distributed system
US6483825B2 (en) Time synchronization method in CDMA system
US7068746B1 (en) Base station transceiver to radio network controller synchronization filtering function
KR101152161B1 (ko) 분산 동기화 방법 및 시스템
WO2014083640A1 (ja) 通信装置、通信システムおよび時刻同期方法
US20080075061A1 (en) Synchronising base stations
US20100138187A1 (en) Estimating a time offset between stationary clocks
CN101675614A (zh) 使网络组件的时钟与另外的网络组件的时钟同步的方法及其网络组件
US6807398B1 (en) Time synchronization system, satellite system applied to the time synchronization system, ground system applied in the time synchronization system, time synchronization method and a computer-readable recording medium with a program
EP2658161B1 (en) Transmission device, transmission method and computer program
JP2003298630A (ja) 時刻同期方法
US6714611B1 (en) Wireless network with user clock synchronization
KR20090071923A (ko) 동기식 이더넷에서 단일 타임 싱크 프레임을 이용한 통신단말 및 브리지 장치의 시간 동기화 방법 및 그 장치
Ferrant et al. Evolution of the standards for packet network synchronization
US6430241B1 (en) Method and configuration for synchronizing system units
EP1659717B1 (en) Phase adjusting method and apparatus
KR20100048124A (ko) 근거리 통신망에서의 시간 동기화 방법
EP3420655B1 (en) Methods and systems for estimating frequency synchronization accuracy
EP3420666B1 (en) Methods and systems for estimating skew

Legal Events

Date Code Title Description
AS Assignment

Owner name: NEC CORPORATION, JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:TANAKA, HIRONAO;REEL/FRAME:010279/0821

Effective date: 19990916

REMI Maintenance fee reminder mailed
LAPS Lapse for failure to pay maintenance fees
STCH Information on status: patent discontinuation

Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362

FP Lapsed due to failure to pay maintenance fee

Effective date: 20071111